All R50/53 seats hould fit with no problems, ........only the later R56 Mk2/Gen 2 MINI's have different underseat wiring connectors but even these can be fitted to earlier MINI's with some mods detailed on various Mini forums.

The park lane seats are also heated (in the uk model anyway) i don't know how cold it gets where you live, but if your car doesn't have that option it might be worth wiring it up,
the BMW retro fitting kit is a fortune I made my own for under £30, and no programing needed.

Yes......don't re-connect the battery or switch on the ignition until the replacement seats wiring is reconnected for the airbags (Yellow connectors) and seatbelt pre-tensioners (blue connectors). Heated seat wiring can be left unconnected if not used on your car as it will not be programmed to expect it.

The park lane seats are also heated (in the uk model anyway) i don't know how cold it gets where you live, but if your car doesn't have that option it might be worth wiring it up,
the BMW retro fitting kit is a fortune I made my own for under £30, and no programing needed.

and two small black boxes from the same company, i fitted it next to the airbag plug under the seat, I extended the 2 wires from the little blue sensor and tucked it in between the foam and heated pad about 2" in at the rear of the seat affixed with cloth tape, the wires that come out of the stock heater pad seat are brown=earth black=sensor (we have bypassed that with our own one) green= 12v+

The seat+ connects to the N/O of the circuit board, power comes from the heated seat fuse of the fusebox through switches in the stock position all earth join together and connect to car body

There is only one heat position but it is adjustable via the circuit board I only like it warm not too hot,